ETL GT2123 C m o s p o s i t i v e v o l t a g e r e g u l a t o r Datasheet

ISSUED DATE :2005/01/24
REVISED DATE :
GT2123
C M O S P o s i t i v e Vo l t a g e R eg u l a t o r
Description
The GT2123 of positive, linear regulators feature low quiescent current (35 A typ.) with low dropout voltage,
making them ideal for battery applications.
This rugged device has both Thermal Shutdown, and Current Fold-back to prevent device failure under the
“Worst” of operating conditions.
The SOT-26 version also features a “Power Good” detector, which pulls low when the output is out of
regulation. The GT2123 is stable with an output capacitance of 2.2 F or greater.
Features
Very Low Dropout Voltage
Guaranteed 300mA output
Over-Temperature Shutdown
Current Limiting
Short Circuit Current Fold-back
Highly Accurate± 1.5%
Adjustable output voltages
Power-saving Shutdown Mode
Power Good Detector
Low Temperature coefficient
Functional Block Diagram
Applications
Battery Powered Widgets
Instrumentation
Wireless Devices
PC Peripherals
Portable Electronics
Cordless Phones
Electronic Scales
Package Dimensions
REF.
A
B
C
D
E
F
Millimeter
Min.
Max.
2.70
3.10
2.60
3.00
1.40
1.80
0.30
0.55
0
0.10
0°
10°
REF.
G
H
I
J
K
L
Dimensions
Millimeter
1.90 REF.
1.20 REF.
0.12 REF.
0.37 REF.
0.60 REF.
0.95 REF.
Typical Application Circuit
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ISSUED DATE :2005/01/24
REVISED DATE :
Absolute Maximum Ratings
Parameter
Symbol
Ratings
Unit
Input Max Voltage
VIN
8
V
Output Current
IOUT
PD/( VIN- VO)
mA
GND-0.3 to VIN+0.3
V
Input, Output Voltage
Operating Ambient Temperature
Junction Temperature
Maximum Junction Temperature
Thermal Resistance
Power Dissipation( T=100 )
Topr
-40 ~ +85
Tj
-40 ~ +125
Tj Max
150
ja
260
/W
PD
380
mW
EDS Classification
B
Electrical Characteristics Ta=25
Parameter
Output Voltage
Output Current
Current Limit
Load Regulation
Symbol
VO
IO
ILIM
REGLOAD
Dropout Voltage
VDROPOUT
Ground Pin Current
Line Regulation
Input Voltage
Over Temperature Shutdown
Over Temperature Hysterisis
Output Voltage
Temperature Coefficient
Short Circuit Current(Note2)
Power Supply Rejection
IGND
REGLINE
Min
TYP
Max
Unit
-1.5%
-
1.5%
V
VIN=5V, VO>1.2
300
-
-
mA
VIN=5V, VO>1.2
300
450
-
mA
VIN=5V, IO=1mA to 300mA
1.5V<VO(NOM) 2.0V
IO=300mA
2.0V<VO(NOM) 2.8V
VO=VO(NOM)-2%
2.8V<VO(NOM)<3.8V
-
0.2
-
1
1300
400
300
%
-
35
-
-
-
0.15
-
0.02
0.1
VIN=5V, IO=1mA~300mA
IO=5mA
VO
V
VIN=VOUT(T)+1 to
VO 2.0V
VOUT(T)+2
mV
A
%
-
7
-
150
30
-
TC
-
30
-
VIN=5V, VOUT<0.8V
f=100Hz
VIN=5V
Io=100mA
f=1kHz
Co=2.2 f
f=10kHz
-
150
60
50
20
300
-
mA
f=10Hz~100kHz
Io=10mA
C BYP=0 F
-
30
-
Vrms
1.2
2.0
0
0
115
-
1
1.215
0.5
-
1.23
VIN
0.4
0.1
0.5
1
0.1
85
1
7
0.4
A
ISC
PSRR
ADJ Input Bias Current
ADJ Reference Voltage
IADJ
VREF
VEH
VEL
IEH
IEL
ISD
VO,SD
VUV
VOV
ILC
VPG
VOL
Shutdown Supply Current
Shutdown Output Voltage
Output Under Voltage
Output Over Voltage
PG Leakage Current
PG Voltage Rating
PG Voltage Low
Condition
VIN=5V, IO=1mA
Note1
eN
EN Input Bias Current
unless otherwise noted
VIN
OTS
OTH
Output Voltage Noise
EN Input Threshold
VIN=5V,
Co=2.2 F
VIN=2.7V to 7V
VIN=2.7V to 7V
VEN=VIN, VIN=2.7V to 7V
VEN= 0V, VIN=2.7V to 7V
VIN=5V, VO=0V, VEN<VEL
Io=35 A, VEN<VEL
VPG=7V
VO in regulation
ISINK=0.4mA
V
ppm/
dB
V
V
A
A
A
V
%Vo(NOM)
%Vo(NOM)
A
V
V
Note 1: VIN (MIN) =VOUT+VDROPOUT
2: To prevent the Short Circuit Current protection feature from being prematurely activated, the input voltage must be applied before
a current source load is applied.
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ISSUED DATE :2005/01/24
REVISED DATE :
Ordering Information ( contd. )
Part Number
GT2123-AD
Marking
3BAD2
XXXX
Output Voltage
Part Number
Marking
Output Voltage
Adjustable
Detailed Description
The GT2123 of COMS regulators contain a PMOS pass transistor, voltage reference, error amplifier,
over-current protection, thermal shutdown and Power Good detection circuitry.
The P-channel pass transistor receives data from the error amplifier, over-current shutdown, and thermal
protection circuits. During normal operation, the error amplifier compares the output voltage to a precision
reference. Over-current and Thermal shutdown circuits become active when the junction temperature exceeds
150 , or the current exceeds 300mA. During thermal shutdown, the output voltage remains low. Normal
operation is restored when the junction temperature drops below 120 .
The GT2123 switches from voltage mode to current mode when the load exceeds the rated output current.
This prevents over-stress. The GT2123 also incorporates current fold-back to reduce power dissipation when
the output is short circuited. This feature becomes active when the output drops below 0.8 volts, and reduces
the current flow by 65%. Full current is restored when the voltage exceeds 0.8 volts.
External Capacitors
The GT2123 is stable with an output capacitance to ground of 2.2 F or greater. Ceramic capacitors have the
lowest ESR, and will offer the best AC performance. Conversely, Aluminum Electrolytic capacitors exhibit the
highest ESR, resulting in the poorest AC response. Unfortunately, large value ceramic capacitors are
comparatively expensive. One option is to parallel a 0.1 F ceramic capacitor with a 10 F Aluminum Electrolytic.
The benefit is low ESR, high capacitance, and low overall cost.
A second capacitor is recommended between the input and ground to stabilize Vin. The input capacitor should
be at least 0.1 F to have a beneficial effect.
All capacitors should be placed in close proximity to the pins. A “Quiet” ground termination is desirable. This
can be achieved with a “Star” connection.
Enable
The Enable pin normally floats high. When actively, pulled low, the PMOS pass transistor shuts off, and all
internal circuits are powered down. In this state, the quiescent current is less than 1 A. This pin behaves much
like an electronic switch.
Power Good
The GT2123 includes the Power Good feature. When the output is not within 10% of the specified voltage, it
pulls low. This can occur under the following conditions:
1) Input Voltage too low.
2) During Over-Temperature.
3) During Over-Current.
4) If output is pulled up.
(Note: PG pin is an open-drain output.)
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ISSUED DATE :2005/01/24
REVISED DATE :
Characteristics Curve
4/8
ISSUED DATE :2005/01/24
REVISED DATE :
5/8
ISSUED DATE :2005/01/24
REVISED DATE :
6/8
ISSUED DATE :2005/01/24
REVISED DATE :
External Resistor Divider Table
R1(K Ohm)
1
2
Vout
5
10
20
50
100
200
500
1000
R2(K Ohm)=(1.215*R1(K Ohm))/(VOUT-1.215)
1.30
14.29
28.59
71.47
142.94
285.88
714.71
1.35
9.00
18.00
45.00
90.00
180.00
450.00
1.40
6.57
13.14
32.84
65.68
131.35
328.38
1.45
5.17
10.34
25.85
51.70
103.40
258.51
517.02
1.50
4.26
8.53
21.32
42.63
85.26
213.16
426.32
852.63
1.55
3.63
7.25
18.13
36.27
72.54
181.34
362.69
725.37
1.60
3.16
6.31
15.78
31.56
63.12
157.79
315.58
631.17
1.65
2.79
5.59
13.97
27.93
55.86
139.66
279.31
558.62
1.70
2.51
5.01
12.53
25.05
50.10
125.26
250.52
501.03
1.75
2.27
4.54
11.36
22.71
45.42
113.55
227.10
454.21
1.80
2.08
4.15
10.38
20.77
41.54
103.85
207.69
415.38
1.85
1.91
3.83
9.57
19.13
38.27
95.67
191.34
382.68
1.90
1.77
3.55
8.87
17.74
35.47
88.69
177.37
354.74
1.95
1.65
3.31
8.27
16.53
33.06
82.65
165.33
330.61
826.53
2.00
1.55
3.10
7.74
15.48
30.96
77.39
154.78
309.55
773.89
2.05
1.46
2.91
7.28
14.55
29.10
72.75
145.51
291.02
727.54
2.10
1.37
2.75
6.86
13.73
27.46
68.64
137.29
274.58
686.44
2.15
1.30
2.60
6.50
12.99
25.99
64.97
129.95
259.89
649.73
2.20
1.23
2.47
6.17
12.34
24.67
61.68
123.35
246.70
616.75
2.25
1.71
2.35
5.87
11.74
23.48
58.70
117.39
234.78
586.96
2.30
1.12
2.24
5.60
11.20
22.40
55.99
111.98
223.96
559.91
2.35
1.07
2.14
5.35
10.70
21.41
53.52
107.05
214.10
535.24
2.40
1.03
2.05
5.13
10.25
20.51
51.27
102.53
205.06
512.66
2.45
0.98
1.97
4.92
9.84
19.68
49.19
98.38
196.76
491.90
2.50
0.95
1.89
4.73
9.46
18.91
47.28
94.55
189.11
472.76
2.55
0.91
1.82
4.55
9.10
18.20
45.51
91.01
182.02
455.06
2.60
0.88
1.75
4.39
8.77
17.55
43.86
87.73
175.45
438.63
877.26
2.65
0.85
1.69
4.23
8.47
16.93
42.33
84.67
169.34
423.34
846.69
2.70
0.82
1.64
4.09
8.18
16.36
40.91
81.82
163.64
409.09
818.18
2.75
0.79
1.58
3.96
7.92
15.83
39.58
79.15
158.31
395.77
791.53
2.80
0.77
1.53
3.83
7.67
15.33
38.33
76.66
153.31
383.28
766.56
2.85
0.74
1.49
3.72
7.43
14.86
37.16
74.13
148.62
371.56
743.12
2.90
0.72
1.44
3.61
7.21
14.42
36.05
72.11
144.21
360.53
721.07
2.95
0.70
1.40
3.50
7.00
14.01
35.01
70.03
140.06
350.14
700.29
3.00
0.68
1.36
3.40
6.81
13.61
34.03
68.07
136.13
340.34
680.67
3.05
0.66
1.32
3.31
6.62
13.24
33.11
66.21
132.43
331.06
662.13
3.10
0.64
1.29
3.22
6.45
12.89
32.23
64.46
128.91
322.28
644.56
3.15
0.63
1.26
3.14
6.28
12.56
31.40
62.79
125.58
313.95
627.91
3.20
0.61
1.22
3.06
6.12
12.24
30.60
61.21
122.42
306.05
612.09
3.25
0.60
1.19
2.99
5.97
11.94
29.85
59.71
119.41
298.53
597.05
3.30
0.58
1.17
2.91
5.83
11.65
11.65
58.27
116.55
291.37
582.73
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ISSUED DATE :2005/01/24
REVISED DATE :
External Resistor Divider Table
R1(K Ohm)
1
2
Vout
5
10
20
50
100
200
500
1000
R2(K Ohm)=(1.215*R1(K Ohm))/(VOUT-1.215)
3.35
0.57
1.14
2.85
5.69
11.38
28.45
56.91
113.82
284.54
569.09
3.40
0.56
1.11
2.78
5.56
11.12
27.80
55.61
111.21
278.03
556.06
3.45
0.54
1.09
2.72
5.44
10.87
27.18
54.36
108.72
271.81
543.62
3.50
0.53
1.06
2.66
5.32
10.63
26.59
53.17
106.35
265.86
531.73
3.55
0.52
1.04
2.60
5.20
10.41
26.02
52.03
104.07
260.17
520.34
3.60
0.51
1.02
2.55
5.09
10.19
25.47
50.94
101.89
254.72
509.43
3.65
0.50
1.00
2.49
4.99
9.98
24.95
49.90
99.79
249.49
498.97
3.70
0.49
0.98
2.44
4.89
9.78
24.45
48.89
97.79
244.47
488.93
3.75
0.48
0.96
2.40
4.79
9.59
23.96
47.93
95.86
239.64
479.29
3.80
0.47
0.94
2.35
4.70
9.40
23.50
47.00
94.00
235.01
470.02
3.85
0.46
0.92
2.31
4.61
9.22
23.06
46.11
92.22
230.55
461.10
3.90
0.45
0.91
2.26
4.53
90.5
22.63
45.25
90.50
226.26
452.51
3.95
0.44
0.89
2.22
4.44
8.88
22.21
44.42
88.85
222.12
444.24
4.00
0.44
0.87
2.18
4.36
8.73
21.81
43.63
87.25
218.13
436.27
4.05
0.43
0.86
2.14
4.29
8.57
21.43
42.86
85.71
214.29
428.57
4.10
0.42
0.84
2.11
4.21
8.42
21.06
42.11
84.23
210.57
421.14
4.15
0.41
0.83
2.07
4.14
8.28
20.70
41.40
82.79
206.98
413.97
4.20
0.41
0.81
2.04
4.07
8.14
20.35
40.70
81.41
203.52
407.04
4.25
0.40
0.80
2.00
4.00
8.01
20.02
40.03
80.07
200.16
400.33
4.30
0.39
0.79
1.97
3.94
7.88
19.69
39.38
78.77
196.92
393.84
4.35
0.39
0.78
1.97
3.88
7.75
19.38
38.76
77.51
193.78
387.56
4.40
0.38
0.76
1.91
3.81
7.63
19.07
38.15
76.30
190.74
381.48
4.45
0.38
0.75
1.88
3.76
7.51
18.78
37.56
75.12
187.79
375.58
4.50
0.37
0.74
1.85
3.70
7.40
18.49
36.99
73.97
184.93
369.86
4.55
0.36
0.73
1.82
3.64
7.29
18.22
36.43
72.86
182.16
364.32
4.60
0.36
0.72
1.79
3.59
7.18
17.95
35.89
71.79
179.47
358.94
4.65
0.35
0.71
1.77
3.54
7.07
17.69
35.37
70.74
176.86
353.71
4.70
0.35
0.70
1.74
3.49
6.97
17.43
34.86
69.73
174.32
348.64
4.75
0.34
0.69
1.72
3.44
6.87
17.19
34.37
68.74
171.85
343.71
4.80
0.34
0.68
1.69
3.39
6.78
16.95
33.89
67.78
169.46
338.91
4.85
0.33
0.67
1.67
3.34
6.69
16.71
33.43
66.85
167.13
334.25
4.90
0.33
0.66
1.65
3.30
6.59
16.49
32.97
65.94
164.86
329.72
4.95
0.33
0.65
1.63
3.25
6.51
16.27
32.53
65.06
162.65
325.30
5.00
0.32
0.64
1.61
3.21
6.42
16.05
32.10
64.02
160.50
321.00
Note: Small load (greater than 2mA) is necessary as R1 or R2 is large than 50Kohm. Otherwise, output voltage probably cannot be
pulled down to 0V on disable mode
Important Notice:
All rights are reserved. Reproduction in whole or in part is prohibited without the prior written approval of GTM.
GTM reserves the right to make changes to its products without notice.
GTM semiconductor products are not warranted to be suitable for use in life-support Applications, or systems.
GTM assumes no liability for any consequence of customer product design, infringement of patents, or application assistance.
Head Office And Factory:
Taiwan: No. 17-1 Tatung Rd. Fu Kou Hsin-Chu Industrial Park, Hsin-Chu, Taiwan, R. O. C.
TEL : 886-3-597-7061 FAX : 886-3-597-9220, 597-0785
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